| Aldershot | |
| Type: | Heavy Bomber |
| First Flight: | October 1921 |
| Introduction: | July 1924 |
| Retired: | March 1926 |
| Produced: | 17 |
| Status: | Retired |
| Variants: | Avro Andover |
The Avro 549 Aldershot was a British single-engined heavy bomber aircraft built by Avro.
The Aldershot was designed to meet the 1920 British Specification 2/20 for a heavy long-range day and night bomber to be powered by a Rolls-Royce Condor engine.[1] The specification required a range of 500 miles (800 km) and a bombload of 2,000 lb (900 kg), originally comprising a single World War I vintage 1,800 lb (820 kg) SN bomb, but then changed to four 500 lb (230 kg) bombs carried externally or eight 250 lb (114 kg) bombs internally.[2] [3] The Air Ministry gave Avro a contract for two prototypes, designated Aldershot I, on 2 December 1920, in competition with the de Havilland Derby.[1]
The first prototype flew at Hamble Aerodrome near Southampton in October 1921.[4] As a result of test flying, the fuselage was lengthened by 6 ft (2 m) in order to improve directional control, being displayed in this form at the RAF Display at Hendon on 24 June, the second prototype flying in July with the lengthened fuselage and a modified undercarriage.[4] [5]
The first prototype was modified as a testbed for the water-cooled Napier Cub engine, in this form becoming the Aldershot II, flying on 15 December 1922.[6] It was later used to test the slow-revving 850 hp (630 kW) Beardmore Typhoon I inline engine, flying in this form on 10 January 1927.[7]
The Aldershot was a three-bay biplane, with a steel-framed fuselage structure with plywood and fabric covering, and wooden wings. The pilot and navigator were seated side by side in a cockpit behind the upper wing trailing edge, with additional accommodation for the navigator who was also the bomb-aimer, in a cabin inside the fuselage, which was provided with four circular windows on each side. A gunner sat in a separate cockpit behind the pilot, and was armed with a Lewis gun on a Scarff ring. Another Lewis gun could be fitted to a ventral mounting in the cabin, while there was provision for a fixed, forward-firing Vickers machine gun operated by the pilot, although this was rarely fitted.[4] A bomb bay forward of the cabin could hold eight 250 lb (114 kg) bombs, with larger bombs being carried externally under the fuselage.[8]
The Aldershot also formed the basis for the Avro Andover transport, which used the same wings, tail and powerplant but had a new fuselage.
When it was evaluated against the de Havilland Derby, the Aldershot proved to be the superior aircraft,[9] with the mixed-construction Aldershot being about 800 lb (360 kg) lighter than the all-wooden Derby, which had no provision for carrying its bombload internally, or for any ventral armament.[10]
On 26 January 1923, the Air Ministry ordered 15 aircraft under the designation Aldershot III.[11] The only operator of the aircraft was No. 99 Squadron RAF which reformed on 1 April 1924,[12] receiving its Aldershots from July that year.[13] The Aldershot was mainly used for night flying, but occasionally flew day bombing exercises. Unlike the other members of the RAF's heavy bomber force, it was operated in an all-silver colour scheme, rather than the dark-green NIVO scheme usually used for night operations.[14] By 1925, the Air Ministry had decided that heavy bombers should have multiple engines, and 99 Squadron started to receive the twin-engined Handley Page Hyderabad in January 1926, with the Aldershots being completely replaced in Squadron service by March that year.